The present invention relates to a pin insertion method and apparatus wherein a hoop-shaped or a straight pin blank in the form of a wire is sequentially cut off into a pin having a predetermined length and pins are inserted into predetermined apertures of a board or the like such as a printed circuit board, the board or the like with inserted pins being a completed part. The present invention particularly relates to a pin insertion method and apparatus which may be used for automatically inserting a single or a plurality of pins made of an electrically conductive material as a terminal or terminals into a predetermined aperture or apertures in a printed circuit board upon which are mounted various electrical and electronic parts and which is highly efficient in operation, inexpensive and capable of correctly inserting the pins in predetermined apertures of a board or the like.
In general, apparatus for inserting square pins (square in cross section) and round pins (circular in cross section) into predetermined apertures in boards or the like are divided into two types. With one type a part preformed in the shape of a square pin is fed to an insertion position through a feed pipe by a part feeder. A plurality of such feed pipes are connected to a die which determines a pin insertion pattern. A board or the like is placed between this die and a female die, and the male and female dies are pressed against each other, whereby a plurality of pins may be simultaneously inserted into predetermined apertures in the board or the like.
With the other type a pin blank in the form of a hoop is cut off into pins which in turn are inserted into predetermined apertures in a board or the like.
The former type has the problems that a large number of parts which are preformed into for instance square pins must be prepared so that the cost is high and that the male and females dies must be changed as the pin insertion pattern is changed so that the initial cost is high and it takes a long time for the replacement of the male and female dies.
The latter type also has some problems. First, the pin blank is fed by a feed pawl, but in order to prevent damage to the pin blank, the pressure exerted on the pin blank from the feed pawl must not so excessive that slip of the pin blank results. As a consequence the pin blank cannot be cut into a pin having a predetermined length, and the cutoff pins vary in length from one pin to another. Furthermore cutting requires a high power. Since the pin insertion member is rotated, the pin tends to fall off. As a result a high pin insertion speed cannot be attained. Furthermore, because of shearing burrs are formed at the sheared edge so that the cut area of the pin becomes greater than the original cross sectional area of the pin blank and consequently cannot be inserted into an aperture and damages the board or the like.
Both types have a common problem that the faces of inserted square pins are oriented in random directions.